If a sample of pure silver (ag) contains 3.35 x 1022 atoms of silver, how many moles of silver are in the sample? a) 17.9 mol b) 2.82 mol c) 0.180 mol d) 0.0556 mol

the answer is D 0.0556 mol

divide the given number of atoms 3.35x10^22 by 6.02x10^23 Avogadro's number(the number of atoms in one mol of anything) to get the total number of Moles. It's merely a fraction of a whole. 3.35/60.2 if you cancel out the tens.   1.0 mol mercury(the molar mass is the mass number on a periodic table) It couldn't possibly be so few atoms is to be gold or atoms of mercury as there are 6.02x10^23 atoms in a 0.0556 mol.  

have a nice day hope this helps

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml